Orthogonal frequency-division multiplexing (OFDM) and orthogonal frequency division multiple access (OFDMA) wireless communication systems under IEEE 802.16 use a network of base stations to communicate with wireless devices (i.e., mobile stations) registered for services in the systems based on the orthogonality of frequencies of multiple subcarriers and can be implemented to achieve a number of technical advantages for wideband wireless communications, such as resistance to multipath fading and interference. Each base station (BS) emits and receives radio frequency (RF) signals that convey data to and from the mobile stations.
In current versions of the IEEE 802.16 standard, a base station (BS) may broadcast one or more media access control (MAC) management messages to the mobile stations (MSs) to which service is provided. At times, the parameters of a MAC management message may change resulting in a new version of the MAC management message. The new version of the MAC management message may then be sent to the MSs allowing the MSs to reconfigure to accommodate the new parameters. These changes may be tracked by a configuration change counter (CCC).
However, there may be situations in which it is convenient for an MS to negotiate periods of unavailability in an effort to conserve power. Consequently, if an MS is in an unavailable state when a MAC management message broadcasts the new version of the MAC management message, the MS may not receive the MAC management message. This may result in a mismatch between the current version of the MAC management message and the configuration of the MS.
If there is a mismatch between the configuration of the MS and the DL-MAP information included in the PDUs, the MS may discard subsequent PDUs until the MAC management parameters are updated and the MS receives PDU messages with matching DL-MAP information. As a result, the MS may lose all data packets transmitted before the MAC management parameters and the DL-MAP information are synchronized resulting in a drop in data throughput.
In some scenarios, the MS may have to wait for 30 seconds before receiving a PDU including matching MAC management parameters because the BS may not be aware of the situation. Also, the MS may experience increased power consumption even if the PDUs do not require action on the part of the MS, as the MS may wait for the reception of an updated MAC management message before entering a sleep state.